The present invention relates to a power distribution arrangement for an inkjet printhead and in the preferred form to incorporation of such an arrangement as part of the ink supply unit.
The invention has been developed primarily for use in a pagewidth printer utilizing a printhead chip and will be described with reference to such a device. However it will be appreciated that the invention can be applied to other printer types and configurations.
Recently, for example, in PCT Application No. PCT/AU98/00550 the present applicant has proposed a pagewidth inkjet printing device which utilizes micro-electromechanical (MEMS) processing techniques in the construction of a thermal bend actuator type device for the ejection of fluid from a nozzle chamber.
With any compact but fragile page width printhead, substantial currents must be supplied to the printhead whilst printing. This is especially the case where an extremely large number of ink ejection nozzles are utilized.
Additionally, a pagewidth printhead less then say one millimeter in width constructed on a silicon wafer or the like is likely to be extremely fragile and any flexing of the printhead may shatter the wafer.
It is an object of the present invention to provide a power distribution arrangement for an elongate printhead which overcomes or ameliorates one or more of the disadvantages of the prior art or at least offers a useful alternative thereto.
In accordance with a first aspect of the present invention, there is provided a power distribution arrangement and inkjet printhead assembly comprising:
a microelectromechanical elongate inkjet printhead of a kind having a plurality of longitudinally spaced discrete voltage supply points, signal connections and ink supply passages, said printhead mounted in a housing having a series of hydrophobically sealed holes for the ingress of air;
two or more elongate power supply busbars;
a flexible interconnect means folded about the housing, the flexible interconnect means including;
a plurality of connecting lines formed on a first surface thereof connecting a selected plurality of said voltage supply points to said busbars and
a plurality of control line interconnects formed on a second surface thereof connected to the signal connections;
an elongate ink distribution manifold located within said housing having a number of ink outlets in communication with the microelectromechanical elongate inkjet printhead ink supply passages;
clamping means clamping said busbars to the housing;
an ink filter fitted about said ink distribution manifold; and a baffle interposed between the ink distribution manifold and the housing, the baffle including at least one pierceable end wall portion for receiving an ink supply conduit.
Preferably said busbars are disposed to extend parallel to the microelectromechanical elongate inkjet printhead with said connecting lines extend generally transversely therebetween.
In a preferred embodiment the flexible interconnect means comprises a tape automated bonded film.
The flexible interconnect means may further include busbar contacts in the form of deposited noble metal strips, said connecting lines connecting to the selected plurality of said voltage supply points by means of the busbar contacts.
Preferably said interconnect means further includes a plurality of control line interconnects connecting to signal connections on the microelectromechanical elongate inkjet printhead.
The housing may include a series of positioning protuberances for accurately locating the power supply busbars and flexible interconnect means therewith.
In a preferred embodiment the flexible interconnect means is configured to connect only along one edge of the microelectromechanical elongate inkjet printhead.
The busbars may be clamped against the busbar contacts.
Preferably said connecting lines are alternately connected with said busbar contacts and with the plurality of control line interconnects.
Typically the microelectromechanical elongate inkjet printhead includes thermal bend actuator devices for ejection of ink from a plurality of corresponding nozzles formed in said printhead.
The busbars and the flexible interconnect means may be packaged with an associated ink supply unit for delivering ink to the elongate ink distribution manifold.
In a preferred embodiment the elongate ink distribution manifold includes:
a longitudinal slot receiving the microelectromechanical elongate inkjet printhead;
a series of chambers for the storage of separate color inks formed along the elongate ink distribution manifold, said chambers being interconnected with said [slot] ink outlets for the supply of ink to said printhead ink supply passageways.
Preferably said busbars comprise two mechanically stiff conductive rails.